These methods allow us to query for checkpoints contained within the
linked list by height and height range. This is useful to determine
checkpoints to fetch for chain sources without having to refer back to
the `LocalChain`.
Currently this is not implemented efficiently, but in the future, we
will change `CheckPoint` to use a skip list structure.
8ab58af093ff295b86c3f8189aa96dea313092c4 feat(chain)!: wrap `TxGraph` txs with `Arc` (志宇)
Pull request description:
### Description
This PR makes `TxGraph` store transactions as `Arc<Transaction>`.
`Arc<Transaction>` can be shared between the chain-source and receiving structures. This allows the chain-source to keep the already-fetched transactions (save bandwith) and have a shared pointer to the transaction (save memory).
Our current logic to avoid re-fetching transactions is to refer back to the receiving structures. However, this means an additional round of locking our receiving structures.
### Notes to the reviewers
This will make more sense once I update the esplora/electrum chain sources to make use of both #1369 and this PR. The result would be chain sources which would only require locking the receiving structures twice (once for initiating the update, and once for applying the update).
### Changelog notice
* Changed `TxGraph` to store transactions as `Arc<Transaction>`. This allows chain-sources to cheaply keep a copy of already-fetched transactions.
### Checklists
#### All Submissions:
* [x] I've signed all my commits
* [x] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)
* [x] I ran `cargo fmt` and `cargo clippy` before committing
#### New Features:
* [ ] I've added tests for the new feature
* [x] I've added docs for the new feature
ACKs for top commit:
LLFourn:
ACK 8ab58af093ff295b86c3f8189aa96dea313092c4
notmandatory:
ACK 8ab58af093ff295b86c3f8189aa96dea313092c4
Tree-SHA512: 81d7ad35fed7f253a3b902f09a41aaef2877f6201d4f6e78318741bf00e4b898a8000d878ffcbfe75701094ce3e9021bd718b190a655331a9e11f0ad66bdb02f
- changes the code implementation to "the maximum number of consecutive unused addresses"
in esplora async and blocking extjensions.
- treat `stop_gap = 0` as `stop_gap = 1` for all purposes.
- renames `past_gap_limit` to `gap_limit_reached` to indicate we want to break once the gap
limit is reached and not go further in `full_scan`, as suggested in
https://github.com/bitcoindevkit/bdk/issues/1227#issuecomment-1859040463
- change the tests according to the new implementation.
- add notes on what `stop_gap` means and links to convergent definition in other
Bitcoin-related software.
Closes#1227
Wrapping transactions as `Arc<Transaction>` allows us to share
transactions cheaply between the chain-source and receiving structures.
Therefore the chain-source can keep already-fetched transactions (save
bandwidth) and have a shared pointer to the transactions (save memory).
This is better than the current way we do things, which is to refer back
to the receiving structures mid-sync.
Documentation for `TxGraph` is also updated.
